The present invention is relates to fixation devices or anchors and tools and methods for emplacing the same. The present invention, in particular, relates to medical anchors, for example, suture anchors or prosthesis anchors. The invention further relates to a method and apparatus for implanting such devices in biological materials, for example bone. Even more particularly, the present invention relates to a medical anchor which can be inserted through a longitudinally or even curved extending bore hole so that the anchor is initially substantially aligned with the bore hole, and then, the emplacement tool manipulated so that the anchor pivots to form an undercut in the bore hole. The present invention is particularly suitable for the emplacement of anchors adapted to repair ligaments, for example rotator cuff ligaments, interior cruciate ligaments (ACL's) and other ligaments. The anchor is also suitable for prosthesis fixation.
In applicant's U.S. Pat. No. 6,117,161, a medical anchor is disclosed which can be emplaced in a groove which extends substantially parallel to the surface of the bone and then rotated along an axis defined by an employment tool and which axis is perpendicular to the extent of the groove to form an undercut in the walls of the groove to secure the anchor.
In applicant's U.S. Pat. No. 6,102,934, a medical anchor is disclosed which can be emplaced in a borehole so that the anchor is initially substantially aligned with the borehole and then, via an emplacement tool, manipulated so the anchor pivots in two axes to form an undercut in the borehole.
In applicant's co-pending U.S. patent application Ser. No. 09/580,777 filed May 26, 2000, a medical anchor is disclosed which can be emplaced in a bore hole so that the anchor is initially substantially aligned with the bore hole and then, using an emplacement tool, rotated about the axis of the tool. A deploy spring causes the anchor to deploy and rotate about an axis perpendicular to the axis of the tool to initially engage the borehole. Further rotation of the tool causes the anchor to cut into the borehole. The rotation by the user and action of the spring causes the anchor to screw into the borehole as it turns on two axes.
Applicant is also aware of U.S. Pat. No. 5,203,787 to Noblitt et al. in which a suture anchor can be emplaced in bone. Applicant is also aware of U.S. Pat. No. 5,569,302 to Johnson for an apparatus and method for attaching an anchor to bone.
The requirement of U.S. Pat. No. 6,117,161 to form a groove into the surface of the bone prior to emplacing the anchor in some instances may be a deficiency. By forming a groove in the bone, the more dense cortical layer of bone is removed, thus compromising the fixation capability of any anchor. Further, the anchor and tool designs of U.S. Pat. No. 6,102,934 and application Ser. No. 09/580,777 filed May 26, 2000 are more complex due to the rotation of the anchor in two axes. Both of these designs typically require a rotational force to be applied to the tool to set the anchor.
Modern trends in surgery include the restoration of bodily function and form, i.e., repair of anatomical structures through the use of minimally invasive surgical techniques. The ability to surgically repair damaged tissues or joints creating as few and as small incisions as possible produces less trauma, less pain and better clinical outcomes in general.